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Programming Articles
Page 9 of 2545
PHP round() Function
Definition and UsageThe round() function proves useful in rounding any floating point number upto a desired precision level. Positive precision parameter causes the number to be rounded after decimal point, whereas with negative precision, rounding occurs before decimal point. Precision is 0 by default.For example, round(10.6) returns 11, round(10.2) returns 10. The function always returns a floating point number.This function also has another optional parameter called mode takes one of the redefined constants described later.Syntaxround ( float $value , int $precision , int $mode ) : floatParametersSr.NoParameter & Description1valueA float number to be rounded2precisionnumber of decimal digits to round to. ...
Read MorePHP sin() Function
Definition and UsageThe sin() function returns the sine ratio of given angle in radians. In trigonometry, sine of an angle is defined as ratio of lengths of opposite side and hypotenuse.sin(x) = opposite/hypotenuseIf x=90 degree, sin(x) = 1 as opposite side of right angle is a hypotenuseThis function returns a float value.Syntaxsin ( float $arg ) : floatParametersSr.NoParameter & Description1argA floating point value that represents angle in radiansReturn ValuesPHP sin() function returns sine ratio of given parameter.PHP VersionThis function is available in PHP versions 4.x, PHP 5.x as well as PHP 7.x.ExampleOutputThis will produce following result −sin(3.1415926535898) = 1.2246467991474E-16
Read MoreHow to create a line chart for a subset of a data frame using ggplot2 in R?
Subsetting is not a difficult thing in R but if we make our code short then it is a little tedious task because we will have to introduce code between codes and that creates confusion. Therefore, we must be very careful while writing a code inside another code. To create a line with subsetting the data frame using ggplot function of ggplot2 can be done by using subset function.Exampleggplot(subset(df,x1 %in% c("Sample1","Sample2","Sample3")))+ + geom_line(aes(x2,x3,group=x1,colour=x1))Output
Read MoreHow to add or multiply each element of a matrix to the corresponding element of another matrix in R, if these matrices are stored as a list?
Basic mathematical operations such as addition, subtraction, multiplication, and division are common for matrices and we often do that but if the matrices are stored as a list in R then these basic calculations are done differently as they are not direct objects. To add or multiply the matrices in a list, we can use Reduce function with the plus (+) or multiply (*) sign and the list name.ExampleMatrices_List
Read MorePHP sqrt() Function
Definition and UsageThe sqrt() function returns square root of a positive float number. Since square root for negative number is not defined, it returns NAN. This is one of the most commonly used functions.This function always returns a floating point number.Syntaxsqrt ( float $arg ) : floatParametersSr.NoParameter & Description1arga number whose square root is to be obtainedReturn ValuesPHP sqrt() function returns square root of the given arg number. For negative number, the function returns NAN.PHP VersionThis function is available in PHP versions 4.x, PHP 5.x as well as PHP 7.x.ExampleOutputThis will produce following result −sqrt(-1) = NAN
Read MoreHow to create a new data frame for the mean of rows of some columns from an R data frame?
Finding row means help us to identity the average performance of a case if all the variables are of same nature and it is also an easy job. But if some of the columns have different type of data then we have to extract columns for which we want to find the row means. Therefore, we can create a new data frame with row means of the required columns using rowMeans function.Examplerow_means_3.4_cols_df
Read MorePHP srand() Function
Definition and UsageThe srand() function is used to seed the random number generaror. Seeding initializes the random number generator. Most random number generators need initial seeding. In PHP, use of srand() function is optional as it is done automatically.This function doen't have any return value.Syntaxsrand ([ int $seed ] ) : voidParametersSr.NoParameter & Description1seedan integer to be used as seed. If not given, a random number is givenReturn ValuesThis function doesn't return any value.PHP VersionThis function is available in PHP versions 4.x, PHP 5.x as well as PHP 7.x.ExampleOutputThis may produce following result−rand()=548287992
Read MorePHP tan() Function
Definition and UsageThe tan() function returns the tangent ratio of given angle in radians. In trigonometry, tangent of an angle is defined as ratio of lengths of opposite side and adjacent side.tan(x) = opposite/adjacenttangent of an angle is also defined as ratio of its sine and cosinetan(x) = sin(x)/cos(x)If x=45 degree, tan(x) = 1 as in a right angled traingle, opposite and adjacent sides are qual.This function returns a float value.Syntaxtan ( float $arg ) : floatParametersSr.NoParameter & Description1argA floating point value that represents angle in radiansReturn ValuesPHP tan() function returns tangent ratio of given parameter.PHP VersionThis function is available in PHP versions 4.x, PHP ...
Read MoreHow to a split a continuous variable into multiple groups in R?
Splitting a continuous variable is required when we want to compare different levels of a categorical variable based on some characteristics of the continuous variable. For example, creating the salary groups from salary and then comparing those groups using analysis of variance or Kruskal-Wallis test. To split a continuous variable into multiple groups we can use cut2 function of Hmisc package −Exampledf$Salary_Group
Read MoreMatching Nonprintable Characters using Java regex
There are 7 common non printable characters used in general and each character has its own hexadecimal representation.NamecharactersHexa-decimal representationbell\a0x07Escape\e0x1BForm feed\f0x0CLine feed0x0ACarriage return\r0X0DHorizontal tab\t0X09Vertical tab\v0X0BExample 1import java.util.Scanner; import java.util.regex.Matcher; import java.util.regex.Pattern; public class RegexExample1 { public static void main(String[] args) { Scanner sc = new Scanner(System.in); System.out.println("Enter input text: "); String input = sc.nextLine(); String regex = "\x09"; //Creating a pattern object Pattern pattern = Pattern.compile(regex); //Matching the compiled pattern in the String Matcher matcher = ...
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